Thats why I question that water vapor molecules can "freeze" inside of pores too small for water molecules.
Gore Tex has done an excellent job in not telling the whole story about it's membrane. I hesitate to comment here, but feel a slight need based on some inaccurate information...
Gore Tex, after realizing their first generation was failing because of oil and dirt contamination, did something that would greatly effect it's breathablility. They added an additional layer of material, polyurethane (PU), to combat the oils put out by the body. This layer is oeliophobic or "oil-hating" and is necessary to keep the Gore Tex membrane (ePTFE) from leaking (yes, Gore Tex can leak!). In reality, Gore Tex is 80% space. Without the surface energy created by the hydrophobic ePTFE membrane, Gore Tex would leak which is exactly what happened with the first generation of Gore. The oils broke down this surface energy. It is interesting to note that Gore Tex has only changed slightly since the second generation was introduced (Gore XCR and the newer Pro Shell still use the PU layer).
The problem with this layer is that it is a hydrophilic (water loving) monolithic, or solid, layer. In other words, water has to "diffuse (traveling from a greater concentration to a lesser concentration)" through it in order to reach the microporous Gore Tex layer. Thus Gore Tex's breathability is totally reliant upon this PU membrane for it's breathability. Because of this, Gore Tex is at its highest breathability when there is a 100% humidity level inside the jacket, tent, etc. That is why one needs to build up vapor and heat pressure inside the garment, tent, or whatever to "push" the condensation out. Gore Tex does not work at low humidity levels because of this PU membrane which may account for frost or liquid buildup inside a tent. This is also why it is nearly impossible to find a Gore Tex tent.
On the other hand, eVent doesn't have a PU membrane and is therefore very effective at low humidity levels. It is the premiere membrane for single wall tents, but unfortunately doesn't pass outdated fire retardancy tests. eVent is also an ePTFE membrane, but uses instead a hydrophobic (water hating) polymer infused by a super-critical gas treatment to encapsulate the pours of the Teflon membrane to achieve it's oil-hating (oeliophobic) characteristics. Thus it is truly a microporous membrane. This equates to it being 30% (at high humidity levels) to 200% (at low humidity levels) more breathable than Gore Tex!
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Believe, then you will Understand...
There are a lot of theories and anecdotal evidence about single-walled WP/B performance in below freezing conditions, but I'd like to point out another contributing factor to breathability (or the lack thereof). The flame retardant treatment used to pass CPAI-84 tests affects both the weight and the breathability of the tent. For example, the Epic tents made by Black Diamond do not pass this test, and thus cannot be sold in California, Canada, Michigan, etc. (Check the listing at REI.com for the LightHouse).
At one time, both Integral Designs and Bibler offered their tents in both CPAI-84 spec and also without the flame retardant treatment. I remember one poster saying that she used an ID MKIII on the Appalachian Trail and had a miserable time with condensation during the summer. I asked if the tent had a tag with the CPAI-84 statement, and she said that hers did. My ID MKIII doesn't meet the spec, and it's fine for breathability.
All of the Biblers that I have are non flame-retardant with the exception of a Pinion, and they are generally fine in the cold and the rain. But there are differences: the Eldorado and I-Tent have superb ventilation with the roof vents and and the doors that have three zippers so you can vent both from below (stake out the little flap at the bottom of the exterior door) and from above (protected by the wired brim). But the Torre tent has no roof vents (and also built in vestibules), so it is more prone to frosting up on the ceiling (and of course the poles and the seam tape).
But I think I read once in some Bibler literature that the bigger the tent, the less condensation. I have an unusual Bomb Shelter that was probably made for the Special Forces. Instead of ToddTex, it has GoreTex (says so on the inside) with the same type of scrim as found on jackets. Not only is it supremely dry inside under all conditions (even without roof vents), it is also big. I don't know what to attribute this to: perhaps GoreTex is more breathable than ToddTex, perhaps the lighter scrim (also found on eVent tents) is better at passing moisture than the fuzzy nexxus stuff, or perhaps bigger is better.
Here, I've found the statement from Bibler about condensation vs. size:
Do I have to "heat up" the tent's interior to make it breathe?
The myth about single wall tents is that they require a pressure differential, interior to exterior, in order to breathe and prevent condensation. If this were true, you would find less condensation in a smaller tent or bivy sack than in a larger tent. In fact, the larger the surface area of fabric, ie: the bigger the tent, the less condensation occurs.
Registered: 09/12/03
Posts: 144
Loc: Land of the Rockies
Hi Rick -
I've used my Integral Designs MK1XL in temps from ~90F to -30F. Mine has 2 full size doors and no roof vents. I noticed condensation formed on the walls when it was -30F because i closed the doors completely (i know bad bad bad), but until then only minor condensation on the tent poles.
HEY! I just reckymembered sumthin' from one of these sites' forums.
A backpacker said that using a VBL in your sleeping bag would lessen the amount of frost inside your tent. Yery astute observation.
Personally I'd LIKE to use VBL clothing inside my bag instead of a VBL bag liner. The clothing could then be a multiple use item. But... methinks too much vapor would leak out of the neck and cuff areas. Thus a bag liner would seem to be more effective.
Eric
Edited by 300winmag (11/27/0711:49 PM)
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"There are no comfortable backpacks. Some are just less uncomfortable than others."
Just to add to what you've said here Carter - Black Diamond does currently offer the Bibler tents in both the non-flame as well as the flame retardant versions. I recently purchased two Eldorado tents, one from REI and another from Backcountry, the REI tent is a flame retardant tent (probably b/c they have stores in most/all states and it helps them avoid legal issues), whereas the Backcountry tent specifies that "it is not fire proof and is not made with fire retardant material". An additional plus of the non flame retardant tents (b/c they are not coated with the chemical) is that they are a smidge lighter.
Quote:
There are a lot of theories and anecdotal evidence about single-walled WP/B performance in below freezing conditions, but I'd like to point out another contributing factor to breathability (or the lack thereof). The flame retardant treatment used to pass CPAI-84 tests affects both the weight and the breathability of the tent. For example, the Epic tents made by Black Diamond do not pass this test, and thus cannot be sold in California, Canada, Michigan, etc. (Check the listing at REI.com for the LightHouse).
At one time, both Integral Designs and Bibler offered their tents in both CPAI-84 spec and also without the flame retardant treatment. I remember one poster saying that she used an ID MKIII on the Appalachian Trail and had a miserable time with condensation during the summer. I asked if the tent had a tag with the CPAI-84 statement, and she said that hers did. My ID MKIII doesn't meet the spec, and it's fine for breathability.
All of the Biblers that I have are non flame-retardant with the exception of a Pinion, and they are generally fine in the cold and the rain. But there are differences: the Eldorado and I-Tent have superb ventilation with the roof vents and and the doors that have three zippers so you can vent both from below (stake out the little flap at the bottom of the exterior door) and from above (protected by the wired brim). But the Torre tent has no roof vents (and also built in vestibules), so it is more prone to frosting up on the ceiling (and of course the poles and the seam tape).
But I think I read once in some Bibler literature that the bigger the tent, the less condensation. I have an unusual Bomb Shelter that was probably made for the Special Forces. Instead of ToddTex, it has GoreTex (says so on the inside) with the same type of scrim as found on jackets. Not only is it supremely dry inside under all conditions (even without roof vents), it is also big. I don't know what to attribute this to: perhaps GoreTex is more breathable than ToddTex, perhaps the lighter scrim (also found on eVent tents) is better at passing moisture than the fuzzy nexxus stuff, or perhaps bigger is better.
Here, I've found the statement from Bibler about condensation vs. size:
Do I have to "heat up" the tent's interior to make it breathe?
The myth about single wall tents is that they require a pressure differential, interior to exterior, in order to breathe and prevent condensation. If this were true, you would find less condensation in a smaller tent or bivy sack than in a larger tent. In fact, the larger the surface area of fabric, ie: the bigger the tent, the less condensation occurs.
Registered: 10/30/03
Posts: 4963
Loc: Marina del Rey,CA
Quote:
Just to add to what you've said here Carter - Black Diamond does currently offer the Bibler tents in both the non-flame as well as the flame retardant versions. I recently purchased two Eldorado tents, one from REI and another from Backcountry, the REI tent is a flame retardant tent (probably b/c they have stores in most/all states and it helps them avoid legal issues), whereas the Backcountry tent specifies that "it is not fire proof and is not made with fire retardant material". An additional plus of the non flame retardant tents (b/c they are not coated with the chemical) is that they are a smidge lighter.
I wrote to BD about this. Here is the answer I got back:
"Thanks for the email. Most of our Bibler tents are manufactured in non fire-retardant models and for the 6 or 7 states that require it we make an identical fire-retardant version. The Eldorado model is available only in a non FR version. Any of the Fire-retardant models see an average increase in weight of about 8-12 ounces. I hope this helps."
Therefore, whoever told you one of your Eldorados is made of fire retardant material is wrong.
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Don't get me started, you know how I get.
Thats not something I was told Tom - That was my first-hand experience - I have both versions. Two similar labels but one (on the REI tent), very distinctly states that 'it IS made with fire retardant material' and the other (the Backcountry tent) states that 'it is NOT.....and will burn). Spoke to Jeff at Black Diamond about it Thursday or Friday of last week. He was perplexed as well and thought that perhaps REI may carry both versions. Apparently it is possible to purchase all Bibler models, (or at least the Eldorado), with or without the fire retardant coating.I'm pretty sure the Tempest can be purchased either way as well, as I had spoken to someone a while back about that particular model. So I guess it's 'caveat emptor', if one is concerned about breath-ability with respect to flame-retardant tents.
Registered: 10/30/03
Posts: 4963
Loc: Marina del Rey,CA
That is odd, because what BD told me is that they don't make Eldorados with flame retardant. Maybe they did at one time and that one is old stock, but that would be a guess.
You would think that the maker would know what they are selling, but perhaps the customer service rep was mistaken. There is always the possibility the tent was mislabeled. One way to find out is to weigh both of them. The fire retardant adds 8-12 oz, according to BD.
If you are curious, email them and see what they tell you. As long as you aren't cooking in your tent, it probably isn't all that relevant.
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Don't get me started, you know how I get.
Never to late for an update. I did three multi day camps last winter, totalling about a dozen nights in my Early Winters tent. The night time temperatures ranged from -5C (23F) to -17C (1F). In all case the first night I slept with both the door and rear window closed. In all cases there were varying degrees of condensation on the inside of the tent. The second night I opened the door and window (see picture below) and in all cases there was no condensation of any kind. So, as unscientific as this is, I think I can say that Gore Tex breathes very little, if at all, in sub zero temperatures. At about 2.2 kg (4.9 lb) this has become my go to winter tent. I will do some more testing this winter. <img src="/forums/images/graemlins/grin.gif" alt="" />
Boy, that brings back memories, I bougt one exactly like yours in 1977 or '78 and used it intensely for many years until it was sunbleached almost white. I actually lived in it for over a month one spring some 50 miles into the Flathead Valley in SE-BC and had it in humungous winds, heavy snow dumps and bitter cold many times.
My floor finally gave up and when I contacted Rainy Pass about replacement, the cost was such that I decided to simply let the old and dear "friend" go. I kept it in my gear room until about 2005 and then ptiched it....damm near wept, I had SO many good memories of times in that tent.
Bill Nicolai was a brilliant guy and Early Winters were just FINE folks to deal with, Im had clothing, bivies and really neat woolen hats from them, wish they were still in the game. I prefered this tent to the Bibler Solo Dome I replaced it with and never really liked the Bibler, smaller, lighter, too cramped and just not as "cool".
I have gone to Integral Designs as my only singlewall tents, bivies and they are best of all, IME. I will burn a candle lantern to deal with condensation, but, all in all, I prefer singlewall tents for really cold weather camping, just wish that Evan Jones of ID could still make and sell his little MKI-Lite from eVENT, now, THAT was the answer!
Good to see I am not the only one here who remembers Early Winters!
I have an Early Winters light Dimension, but mine does not have the pole running through the middle, nor do I recall seeing that in catalogs. Was this an option? A design change?
Registered: 10/30/03
Posts: 4963
Loc: Marina del Rey,CA
Hey Rick, does that third pole arching over the top make the tent freestanding? It looks like it. Is that a vestibule in front or just the door to the tent itself?
I remember Early Winters. Loved to get their catalog in the mail way back before the Internet. The only thing I bought from them was a candle lantern, which I still have.
Edited by TomD (10/22/0811:15 PM)
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Don't get me started, you know how I get.
It is very close to free standing. The front corners still need to be pulled out. My intention was to enable the tent to withstand a snow load, not so much to make it freestanding. With the mods the tent cannot collapse under load - unless something breaks or rips. Before the mods it would not handle any type of load without the two ends collapsing inwards. There is no vestibule - the inside length is something like 8 or 8 1/2 ft with a total floor area of something like 38 or 40 sq. ft. - lots of room inside. Changes from original include: Easton poles, new pole along the length. cross over strap to stabalize the new pole (I split the seams to sew this directly into the tent body), pole sleeves to capture the new pole and stretch the tent length wise, and a pocket on the beak to hold it up and out from the tent with the new pole. This being the Granddaddy of tunnel tents (about 40 years old), is was nice to obtain it from a member on this site for a very reasonable price and breath some new life into it. (I would buy another one if anybody has one that's not being used.) Here are a couple of more pictures:
Very clever design changes. Did the Easton poles reduce the weight from the original fiberglass poles? I'm not about to give up my Light Dimension, in fact I'd love to pick up an Early Winters Winter Light and, or a Marmot Taku.
The original Fiberglass poles weigh 210 gm (7.4 oz) and the replacement Easton poles weigh 330 gm (11.6 oz) not included the new pole. One of the original poles was broken which necessitated to change.
Sure would like to see a picture of the Winter Light.